Step 4 is open label. Regimens include two or three NRTIs plus EFV, ATV, ritonavir-boosted ATV, or TDF. Clinical assessments and laboratory evaluations are done at entry, at Weeks 2, 4, 6, 8, 12, 16, 20, 24, and then every 8 weeks thereafter for the duration of the study. Evaluations are also required when a protocol-allowed drug substitution is made.